Grease a 900ml pudding basin and line the base with greaseproof paper.
Mix flour, breadcrumbs, suet, orange zest, and sugar in a large bowl.
Dilute orange juice with water to reach 200ml and stir into the suet mixture.
Knead the dough lightly on a floured surface until soft.
Roll two thirds of the dough to a 5mm thickness and line the basin.
Layer sugar, butter cubes, and lemon slices inside the basin until ingredients are used.
Roll the remaining dough, brush with water, and seal it over the pudding.
Cover the basin with pleated paper and foil, then tie with string.
Place on a trivet in a saucepan and fill with boiling water halfway up the sides.
Simmer for 3.5 hours, topping up the water as needed.
Rest for three minutes, remove coverings, and invert onto a plate to serve.